Method and apparatus for manufacturing a composite sheet

Abstract

In a method of manufacturing a stretchable composite sheet, the first continuous sheet is stretched while being transported from a first nip area to a second nip area. The first continuous sheet is either a sheet in which stretchability has already been developed or a sheet in which stretchability has yet to be developed. An opening is formed in the first continuous sheet intermittently in the transport direction, while transporting the first continuous sheet from the second nip area to a third nip area after the stretching operation. A second continuous sheet having a lower stretchability than the first continuous sheet is overlapped and adhered to the first continuous sheet in the third nip area.

1 . A method of manufacturing a stretchable composite sheet, by setting a plurality of nip areas arranged along a transport direction of a first continuous sheet, the first continuous sheet being transported while being sandwiched between rotating rolls in the nip areas, and by passing through the nip areas, as the first continuous sheet, a sheet in which stretchability is developed in the transport direction by being extended in the transport direction, comprising:
 extending the first continuous sheet in the transport direction, while transporting the first continuous sheet from a first nip area to a second nip area, the first continuous sheet being either a sheet in which stretchability has already been developed or a sheet in which stretchability has yet to be developed;   forming an opening in the first continuous sheet intermittently in the transport direction, while transporting the first continuous sheet from the second nip area to a third nip area, the first continuous sheet being in a state of having been extended; and   adhering in an overlapping manner a second continuous sheet having a lower stretchability than the first continuous sheet to the first continuous sheet, in the third nip area.   
     
     
         2 . A method of manufacturing a composite sheet according to  claim 1 , wherein
 a set value of a peripheral speed of rolls that form the second nip area is faster than a set value of a peripheral speed of rolls that form the first nip area, and   a set value of a peripheral speed of rolls that form the third nip area is the same as the set value of the peripheral speed of the rolls that form the second nip area.   
     
     
         3 . A method of manufacturing a composite sheet according to  claim 2 , wherein
 in the forming of the opening, the first continuous sheet is wrapped around a peripheral surface of one roll of a pair of rolls, which are rotated in the transport direction as a rotating direction, at a predetermined wrapping angle and is transported by a rotation of the one roll, and while being transported, as the first continuous sheet is passed through a gap between the pair of rolls, the first continuous sheet is sandwiched and pressed between the peripheral surface of the one roll and a convex part on a peripheral surface of the other roll of the pair of rolls, and the opening is formed on the first continuous sheet, and
 the third nip area is set on the peripheral surface of the one roll. 
   
     
     
         4 . A method of manufacturing a composite sheet according to  claim 2 , wherein
 in the forming of the opening, the first continuous sheet is wrapped around the peripheral surface of the one roll of the pair of rolls, which are rotated in the transport direction as the rotating direction, at the predetermined wrapping angle and is transported by the rotation of the one roll, and while being transported, as the first continuous sheet is passed through the gap between the pair of rolls, the first continuous sheet is sandwiched and pressed between the peripheral surface of the one roll and the convex part on the peripheral surface of the other roll of the pair of rolls, and the opening is formed on the first continuous sheet, and   the second nip area is set on the peripheral surface of the one roll.   
     
     
         5 . A method of manufacturing a composite sheet according to  claim 1 , wherein
 at least between a position of the gap in which the opening is formed and a position of the third nip area, both edges of the first continuous sheet in the width direction are restrained by a restraining member so as to make the first continuous sheet unable to shrink inwards in the width direction.   
     
     
         6 . An apparatus for manufacturing a stretchable composite sheet, by setting a plurality of nip areas arranged along a transport direction of a first continuous sheet, the first continuous sheet being transported while being sandwiched between rotating rolls in the nip areas, and by passing through the nip areas, as the first continuous sheet, a sheet in which stretchability is developed in the transport direction by being extended in the transport direction, comprising:
 rolls that form a first nip area; rolls that form a second nip area; and rolls that form a third nip area,   the first continuous sheet being extended in the transport direction while being transported from the first nip area to the second nip area, the first continuous sheet being either a sheet in which stretchability has already been developed or a sheet in which stretchability has yet to be developed,   an opening being formed intermittently in the transport direction in the first continuous sheet, while the first continuous sheet is being transported from the second nip area to the third nip area, the first continuous sheet in a state of having been extended,   a second continuous sheet having a lower stretchability than the first continuous sheet being adhered in an overlapping manner to the first continuous sheet, in the third nip area.